Those of us caught in downpours in our shorts or left peeling soggy sausages off the barbecue could probably have told them all along.

The Met Office finally admitted yesterday that the forecasts it gave of ‘dry’ weather last year were ‘not helpful’.

But the organisation’s chief scientist still insisted two-thirds of its long-term forecasts are ‘very helpful’ – without specifying quite what that means for the other third.

In its official guidance to the Department for Environment, Food and Rural Affairs, the Met Office said that last April was likely to be ‘drier than usual’.Instead, of course, it turned into a washout that spilled over into the rest of 2012 – which became the wettest year since records began.

So while the long-term forecast suggested a national drought that was going to get worse, tens of thousands actually found themselves facing widespread flooding. The embarrassing admission came to light thanks to a Freedom of Information request.

An internal document revealed that forecasters had said at the end of March that they expected ‘drier than average conditions for April to June, with April driest’.

But in a report sent later to Defra’s chief scientist, the Met Office admitted: ‘Given that April was the wettest since detailed records began in 1910, and the April May June quarter was also the wettest, this advice was not helpful.’

The Met Office has been so embarrassed by its errors in the past that it stopped issuing long-term forecasts to the public.

Instead, it continues to give ‘probability’ guidance for coming months to Government departments such as Defra which need to plan.

But last year, it seems, its forecast did nothing to help anyone.

Yesterday, Met Office chief scientist Julia Slingo insisted that in almost two-thirds of cases their long term ‘probabilistic’ predictions were ‘very helpful’.

She said of last year’s forecast: ‘In March we were facing really very serious pressures on water resources – a major drought that had been going on for a couple of years. I thought I was right to emphasise the risk of dry conditions continuing as a precautionary principle.’

Still, Professor Sligo was not deterred from making a few predictions for those shivering their way through the Easter weekend.

She suggested better weather would arrive – but not until May.

She said: ‘We certainly see the cold weather continuing at least for the next few days, and potentially into the middle of April. Our monthly forecast looking at April slightly favours cold conditions continuing.

‘Beyond that, I think, into the summer, it’s much more difficult to predict. I think we’re expecting a return to normal conditions into May and then June.’

In the short-term, forecasters say most parts of the country can expect dry and bright spells until Tuesday, although temperatures will remain very low.